that's what they want you to belive. and it saddens me that they are achieving their goals.
as an immigrant, I have always opted out of the scanner with undocumented effectiveness and undocumented health effects with no consequences other than a pat down.
I (think I) get the point you're making and I broadly agree, but in the immigration case (on the way in to the country, rather than the way out) it's more than what they want you to believe: it's what they can and do enforce. For good or ill. And there's very little that you can do about it other than decide to not travel to the USA.
This link[0] is admittedly an advert for legal services, but there are a couple of interesting snippets in there such as:
> ... if you have been refused entry into the United States at any point in the past, even for an expired passport, the previous denial is reasoning enough for future denial.
IANAL but my understanding is that for non-residents there's no legal obligation to admit you outside of maybe some of the international refugee conventions (which are unlikely to apply). The law is deliberately discretionary. A refusal to admit can be based purely on "suspicion". You can imagine a CBP officer finding you suspicious (rightly or wrongly) because you refuse to hand over your passwords even if they don't have a legal right to force you to hand them over. They can simply offer you a choice of handing them over or going home.
To be clear: I'm not advocating for this state of affairs, but it does appear to be the case.
as an immigrant, I have always opted out of the scanner with undocumented effectiveness and undocumented health effects with no consequences other than a pat down.